Image coding method, image coding apparatus, image decoding method, image decoding apparatus, and image coding and decoding apparatus

Abstract

Image coding and decoding technologies are described. For example, a sample adaptive offset (SAO) type parameter is decoded from a bitstream, and an SAO type for an SAO value to be added to a pixel value of a reconstructed image is determined from the SAO type parameter. A plurality of bins with variable length coding is decoded from the bitstream using bypass arithmetic coding with a fixed probability. The plurality of bins represents an integer indicating a magnitude of the SAO value. The integer indicating the magnitude of the SAO value is determined based on the plurality of bins decoded using bypass arithmetic coding with a fixed probability. The SAO value is determined using the determined integer.

The invention claimed is: 
     
       1. A method comprising:
 determining a sample adaptive offset (SAO) type parameter for a SAO value, wherein the SAO type parameter indicates whether the SAO value is an edge offset value or a band offset value, and the SAO value is to be added to a pixel value of a reconstructed image; 
 encoding the SAO type parameter into a bitstream; 
 determining an integer indicating a magnitude of the SAO value; and 
 encoding the determined integer using variable length coding into a plurality of bins, 
 wherein each bin of the plurality of bins is encoded into the bitstream using bypass arithmetic coding with a fixed probability. 
 
     
     
       2. The method of  claim 1 , wherein the fixed probability is a 50% probability. 
     
     
       3. An apparatus, comprising:
 at least one processor; 
 at least one memory including computer program code, the memory and the computer program code configured to, working with the at least one processor, cause the apparatus to perform at least the following: 
 decode a sample adaptive offset (SAO) type parameter from a bitstream; 
 determine from the SAO type parameter an SAO type for an SAO value, wherein the SAO type parameter indicates whether the SAO value is an edge offset value or a band offset value, and the SAO value is to be added to a pixel value of a reconstructed image; 
 decode from the bitstream, using bypass arithmetic coding with a fixed probability, a plurality of bins with variable length coding, wherein the plurality of bins represents an integer indicating a magnitude of the SAO value; 
 determine the integer indicating the magnitude of the SAO value, based on the plurality of bins decoded using bypass arithmetic coding with a fixed probability; and 
 determine the SAO value using the determined integer. 
 
     
     
       4. The apparatus of  claim 3 , wherein the memory and the computer program code are configured to, working with the at least one processor, cause the apparatus to add the SAO value to a pixel value of an image. 
     
     
       5. The apparatus of  claim 3 , wherein the fixed probability is a 50% probability. 
     
     
       6. A method comprising:
 decoding a sample adaptive offset (SAO) type parameter from a bitstream; 
 determining from the SAO type parameter an SAO type for an SAO value, wherein the SAO type parameter indicates whether the SAO value is an edge offset value or a band offset value, and the SAO value is to be added to a pixel value of a reconstructed image; 
 decoding from the bitstream, using bypass arithmetic coding with a fixed probability, a plurality of bins with variable length coding, wherein the plurality of bins represents an integer indicating a magnitude of the SAO value; 
 determining the integer indicating the magnitude of the SAO value, based on the plurality of bins decoded using bypass arithmetic coding with a fixed probability; and 
 determining the SAO value using the determined integer. 
 
     
     
       7. The method of  claim 6 , further comprising adding the SAO value to a pixel value of an image. 
     
     
       8. The method of  claim 6 , wherein the fixed probability is a 50% probability.